Such portable objects are known from the prior art, particularly from Japanese Patent No. 01-284 791, which concerns a diary watch with voice recognition. A vocal interface is provided, allowing the user to introduce his time schedule orally and word recognition means and storage means for processing the received data and then storing the data once processed.
U.S. Pat. No. 6,012,030 presents a portable communication device including a multimode user interface including a vocal interface and a tactile or graphic interface. The portable device can pass automatically from a vocal interface standby mode to a vocal interface active mode when the user selects the vocal interface, or conversely from the active state to the standby state when the user selects another interface.
Such portable devices have, however, several drawbacks. In fact, since these types of device are portable, the user is capable of using them at any time and especially anywhere, for example in public transport or places. It often happens that the external or ambient conditions are altered during use. For example it can happen that the ambient noise becomes excessive so as to make the vocal interface unusable, the voice recognition system no longer being able to interpret correctly the sounds it is receiving. Likewise, it can happen that the ambient light becomes insufficient for the user to use the tactile or graphic interface comfortably. The idea consisting in this latter case in using lighting means is unsatisfactory since these lighting means consume too much energy, moreover, in the case of a tactile screen, a large part of the illumination is filtered by the latter. The use of a user interface also depends on the environment in which the portable object is located, thus, a user interface using a tactile glass or touch sensitive screen or panel for receiving data cannot be used in a liquid environment. Likewise, an interface using radio-frequency signal reception cannot be used in an environment where too many unwanted frequencies are received.
It is an object of the invention to overcome the aforementioned drawbacks, by preventing the user from using an interface, for example a vocal interface, when the latter is no longer able to operate properly, and, as far as possible, allowing the user to still be able to use an operational interface.